A former neuroscience graduate student accused of opening fire at a crowded movie theater also booby-trapped his apartment.
That's the picture emerging about the suspect allegedly responsible for 12 deaths and 59 injuries at an Aurora movie theater early Friday morning. He has been identified as 24-year-old James Holmes.
Holmes is accused of opening fire at a midnight showing of "The Dark Knight Rises." It's the worst mass shooting in the United States since a man opened fire at Fort Hood, Texas in 2009, and the worst in Colorado since the Columbine massacre in 1999.
Holmes was arrested behind the Century 16 movie theater in Aurora. A search of his vehicle uncovered several firearms.
After the suspect alluded to having explosives inside his apartment, authorities broke in through a window, using extreme caution, and placed a camera inside.
The camera revealed a complex series of booby traps. One official reported seeing trip wires strewn throughout the apartment.
"I don't know what all the trip wires are connected to...you can see several string-like contraptions," Deputy Fire Chief Chis Henderson said.
Soda-sized bottles containing an unknown substance were also found inside the apartment. Authorities have not identified the substance, but are treating it as though it is dangerous. Firefighters are staying at a safe distance from the apartment, and say they will battle any fires that erupt from the outside.
Five nearby buildings were also evacuated.
Spokeswoman Jacque Montgomery says Holmes was a neuroscience student at the University of Colorado School of Medicine in Denver until last month. She did not know when he started school or why he withdrew.
Anschutz Medical Campus is conducting a sweep of every building Holmes ever worked in to ensure he left nothing behind before leaving the school. Non-essential personnel have been asked to leave the campus/not report to work through Saturday morning.
The school stresses that with Holmes in custody, they do not believe any students or faculty are at risk.
Aurora police said in a press conference Friday that Holmes has no previous criminal history in Aurora outside of a traffic violation. KKTV 11 News has looked at court documents for the state of Colorado, and have been unable to find any indications of a prior criminal background in the state.
The CBS affiliate in San Diego, KFMB, reports that Holmes' mother lives in the Rancho Penasquitos suburb of that California city. The family has issued a short statement: "Our hearts go out to those involved in this tragedy, and to the families and friends of those involved."